CN-120955250-B - Method for preparing monocrystal ternary lithium anode by recycling waste sodium batteries based on deep eutectic solvent-solvothermal regeneration system

Abstract

A method for preparing a monocrystal ternary lithium anode by recycling waste sodium batteries based on a deep eutectic solvent-solvothermal regeneration system belongs to the field of lithium ion batteries and sodium ion battery recycling. The method comprises the steps of discharging and crushing waste batteries, removing sodium in a waste sodium-electricity positive electrode material by a liquid phase cleaning technology, filtering to obtain waste sodium positive and filtrate with part of sodium removed, adopting polyethylene glycol 200 and a hydrogen bond donor to form a deep eutectic solvent system, selectively leaching the waste sodium positive and the deep eutectic solvent system in a low-temperature environment, centrifugally separating to obtain a sodium-removed active material, completing component reconstruction of the active material and lithium base mixed solution under a temperature control condition, and washing the material subjected to hot-filling of lithium by a solvent to remove residual solution on the surface to obtain the regenerated lithium positive material. Compared with the traditional recovery mode, the method only needs to input manpower and material resources to classify the materials, and greatly reduces the recovery input cost.

Inventors

• SU XIN
• XIANG CONG
• WANG KAIPEI
• ZHANG HAO
• Wan Ruonan
• WANG CONG

Assignees

• 哈尔滨工业大学（威海）

Dates

Publication Date

20260512

Application Date

20250707

Claims (10)

1. 1. A method for preparing a monocrystal ternary lithium anode by recycling waste sodium batteries based on a deep eutectic solvent-solvothermal regeneration system is characterized by comprising the following steps: S1, waste sodium-electricity pretreatment, namely discharging and crushing a waste battery in a proper mode, precisely crushing the discharged retired battery through a multistage deconstructing process to ensure that the positive and negative electrode materials reach 1-100 mu m particle size distribution, and simultaneously dissociating a diaphragm and a shell assembly into fragments of 2-20mm to realize the precise separation of each component; S2, washing, namely removing sodium in the waste sodium-electricity positive electrode material by a liquid phase washing technology, uniformly mixing pure water or an organic solvent with the positive electrode material, and filtering to obtain waste sodium positive and filtrate with part of sodium removed; S3, a deep eutectic solvent is formed by adopting polyethylene glycol 200 and a hydrogen bond donor according to the molar ratio of 14:1, the waste sodium and the deep eutectic solvent system are selectively leached in a low-temperature environment according to the mass ratio of 0.1:5, and the active material subjected to sodium removal treatment is obtained after high-speed centrifugal separation; S4, solvothermal regeneration, namely completing component reconstruction of the mixed solution of the active material and lithium alkali in the S3 under the temperature control condition, and thoroughly removing the surface residual solution of the material subjected to solvothermal lithium supplementation by washing with deionized water twice, so that the regenerated lithium positive material is obtained without excessive treatment; s5, extracting sodium salt, namely filtering filtrate by a nanofiltration membrane, and evaporating and crystallizing the filtrate to obtain sodium sulfate crystals.
2. 2. The method of claim 1, wherein in S1, the multistage deconstructing process is used for efficiently separating and recycling the shell, the current collector and the cathode particles by disassembling, discharging, evaporating, crushing and sorting the retired sodium power.
3. 3. The method according to claim 1 or 2, wherein in S1, the conductive medium is required to completely cover the battery pack during discharging, and the terminal voltage is continuously regulated until the terminal voltage reaches a safety threshold of 2-3V.
4. 4. The method of claim 3, wherein the conductive medium is any one of aluminum powder, copper powder, graphite, or a layered carbon material.
5. 5. The method of claim 1, wherein S2, the uniform mixing requires magnetic stirring at a speed of 1000-2000r/min.
6. 6. The method according to claim 1, wherein in S2, the organic solvent is ethanol or propanol.
7. 7. The method according to claim 1, wherein in S3, the leaching is carried out at a temperature of 25-50 ℃ for a period of 17min-48h.
8. 8. The method according to claim 1, wherein in S4, the solute in the lithium base mixed solution is LiOH, and the concentration is 4mol/L.
9. 9. The method according to claim 1, wherein in S4, the solvothermal temperature is 160-220 ℃ and the treatment is continued for 1-6 hours.
10. 10. The method according to claim 1, wherein in S5, the evaporative crystallization temperature is 100 ℃.

Description

Method for preparing monocrystal ternary lithium anode by recycling waste sodium batteries based on deep eutectic solvent-solvothermal regeneration system Technical Field The invention relates to a method for preparing a monocrystal ternary lithium anode by recycling waste sodium batteries based on a deep eutectic solvent-solvothermal regeneration system, and relates to the field of lithium ion batteries and sodium ion battery recycling. Background In recent years, lithium battery technology has been developed in breakthrough, and lithium ion batteries have been improved significantly in energy density, and meanwhile, cost structures have been changed fundamentally. The dual driving of technology iteration and cost optimization enables the lithium ion battery to rapidly occupy the dominant position of the market, and becomes a core energy storage scheme in the new energy field. Sodium ion batteries are considered to be a substitute for lithium batteries because of their relatively similar chemical properties. However, since the radius of sodium ion is larger than that of lithium ion, sodium or lithium is intercalated in the same structure, and the reaction between the two is greatly different. The polarization of sodium ion batteries is small, which results in a great influence on the structure and diffusion performance, so that the sodium ion batteries replace lithium ion batteries in a heavy and far-reaching way. Currently, lithium ion batteries remain the mainstream. The yield of Lithium Ion Batteries (LIBs) grows exponentially and is a necessary raw material for many industries. But the contents of the key elements nickel, cobalt and manganese required by the lithium ion battery are limited in the crust. While sodium ion batteries have been used in a large number in some industries through development in recent years, the rejection amount of sodium ion batteries has been increasing year by year. The recovery value of sodium in the sodium ion battery is low, and other valuable metals such as nickel, cobalt, manganese and the like still have great recovery value, so that a regeneration technology based on the positive electrode material of the sodium ion battery is developed and converted into a ternary single crystal positive electrode material of the lithium ion battery, and the ternary single crystal positive electrode material of the lithium ion battery becomes a resource recycling strategy with important research value and economic feasibility. The morphology of the ternary lithium positive material has great influence on the performance, and although the positive material with different morphology structures has excellent electrochemical performance, only a few morphologies are excellent when a plurality of factors such as mass preparation, industrial cost, material uniformity, tap density and the like are integrated, and particularly, the single crystal material is more practical. The monocrystal ternary positive electrode material has the advantages of mechanical strength, structural stability, long cycle performance, thermal stability and the like in the aspects of physical and chemical properties, and meanwhile, the high stability and lower specific surface of the monocrystal positive electrode can effectively inhibit side reactions in a battery. Thus, the preparation of the positive electrode material as a single crystal is extremely advantageous. Because of the wide variety and large number of batteries, their recycling is generally divided into two major processes, physical and chemical. The physical process refers to mechanical grinding or manual disassembly, and then different components of the battery are separated, but valuable metals are lost greatly and impurities remain more in the separation process. The chemical process generally refers to pyrometallurgy, hydrometallurgy and direct regeneration, a pyrometallurgical high-temperature heating furnace heats waste batteries at high temperature and decomposes nonmetallic components therein to generate gas and liquid, and the metallic components are fixed in metallic compounds or solid residues at high temperature. However, the waste batteries can generate a large amount of harmful gases such as dioxin, halohydrocarbon, polycyclic aromatic hydrocarbon and the like in the incineration process, and if the waste gases and the heavy metal contained in the harmful gases and the heavy metal contained in the waste gases and the waste residues are not strictly controlled, the environment can be seriously damaged. Hydrometallurgy is to selectively recycle valuable metals in waste batteries through acidic or reducing solution, and the recovery rate is high and the efficiency is high. However, the waste water and a large amount of highly corrosive acid generated by hydrometallurgy consume the waste water and the acid, so that the waste water and the acid still have the defects in the recycling of the contemporary waste batteries. In order to reduce en